Unpowered Wireless Ultrasound Sensor

Abstract

This paper presents a wireless ultrasound sensor that uses frequency conversion to convert the ultrasound signal to a microwave signal and transmit it directly without digitization. Constructed from a few passive microwave components, the sensor is able to sense, modulate, and transmit the full waveform of ultrasound signals wirelessly without requiring any local power source. The principle of operation of the unpowered wireless ultrasound sensor is described first. Implementation of the sensor and the sensor interrogation unit using commercially-available antennas and microwave components is described in detail. Validation of the sensing system using an ultrasound pitch-catch system and the power analysis model of the system are also presented.